//package leetcode.hot100.easy;
//
///* The isBadVersion API is defined in the parent class VersionControl.
//      boolean isBadVersion(int version); */
//class VersionControl {
//    public boolean isBadVersion(int version) {
//        return true;
//    }
//}
//
//class Solution extends VersionControl {
//    public int firstBadVersion(int n) {
//        int left = 1;
//        int right = n;
//        while (left < right) {
//            int mid = left + (right - left) / 2;
//            if (isBadVersion(mid)) {
//                right = mid;
//            } else {
//                left = mid + 1;
//            }
//        }
//        return left;
//    }
//}
//
//public class Test9 {
//}
